That is changing. A new miniature-chip technology from Texas Instruments (TXN) called pico is making digital projectors truly portable, instead of merely luggable. For the past couple of weeks, I’ve been using two of the first pico-based projectors on the market, Dell’s M109S and Optoma’s Pico PK-101.

The products are designed for different customers with different needs. Dell (DELL) positions the 13-ounce M109S as a notebook companion, best suited for work presentations. The four-ounce Optoma projector is designed more as an iPod or digital-camera accessory for watching movies and slide shows on the go.

The Dell M109S

Their portability requires compromises, most obviously in brightness and image resolution. The Dell and Optoma projectors, respectively, support 11 and 50 lumens — a standard measure of projector brightness. That’s far dimmer than top-notch projectors that offer several thousand lumens. So neither product excels in well-lighted rooms, where overhead and ambient lighting overpower their images. You can compensate somewhat for this weakness by placing the devices closer to the surfaces onto which they’re projecting — for example, a wall. But the darker the room you use, the better.

At about the size of a candy bar, the $399 Optoma device is the smaller of the two projectors and the one with the most intriguing possibilities for expanding the tiny screen sizes of mobile devices like the iPod.

It’s powered by a rechargeable battery that Optoma says lasts for an hour on full brightness or two hours on a power-saving setting (the projector comes with two batteries). The projector has a tiny speaker, but people who want decent sound will need to use headphones or external speakers.

In theory, the Optoma device is small enough to bring along on a camping trip to show a film on the side of a tent, or to a restaurant, where you could inflict a vacation slide show on dinner mates by projecting onto a napkin or tablecloth.

I tested it on a recent airplane flight by projecting an episode of “Mad Men” from an iPod touch onto the back of the seat in front of me. The seat was a dark blue with embossing on it, so it didn’t work very well. It’s best to project onto an unmarked, light-colored surface. The quality of the image was better when I lay in bed one night, projecting a video onto a white ceiling.

Even under the most favorable circumstances, however, I found the images from the Optoma projector very dark, muddling the outlines of characters and action on screen. Although Optoma says you can get up to a 60-inch image from the projector, 45 inches was about as big as I could make the image before it got too fuzzy.

Optoma says the projector will ship with an iPod-compatible connector cable when it goes on sale in the U.S. on Dec. 15, though the unit I tested didn’t come with one. I connected the device to my iPod touch using a $50 cable from Apple (AAPL).

Compared with the Optoma device, the $449 Dell M109S is a behemoth, yet it’s still only about the size of a short stack of drink coasters. Most projectors weigh at least a few pounds, if not more, which is big enough to make them a hassle to carry around. I barely noticed the Dell projector inside my laptop bag.

Unlike the Optoma projector, the Dell M109S has to be plugged into an electrical outlet to work. It comes with an unsightly set of connectors for plugging the projector into a video source, such as the VGA port found on most laptops and a composite video plug that is standard on DVD players. I was, however, able to plug my iPod touch into the Dell projector using the $50 Apple cable.

And unlike the Optoma, the Dell doesn’t have speakers. To get sound for a movie, you’ll need headphones or speakers, like those on a laptop.

Despite its extra bulk, the Dell M109S literally outshines the Optoma projector. It produces a bright image that I found very watchable, even if it wasn’t high-definition. I projected the movie “James and the Giant Peach” onto an interior wall of my house, creating an image that was about 7 feet, measured diagonally.

The Dell M109S includes a capability called keystone correction, a standard feature in most projectors that adjusts a projected image to give it the proper dimensions, rather than the trapezoidal shape that results when a projector is angled upward. The Optoma projector doesn’t have this feature. To get a normal rectangular movie image, I had to hold the projector level, toward the projection surface.

For business travelers who do presentations or for people who want to create a theater-like experience in a hotel room, vacation house or against a sheet in the backyard, the Dell projector would be a good fit. For now, the Optoma projector is a good idea that needs refinement.

• Email Nick.Wingfield@wsj.com. Walt Mossberg is on vacation.

But every time I wanted to change songs, I had to go to another room and make a few mouse clicks on my computer. Ever since then, I’ve been waiting for someone to come up with a good, affordable remote control that lets me change tunes no matter where I am in the house.

Apple’s Remote program

It turns out, I already owned that device. It’s an iPod touch. A new program released by Apple (AAPL) in July was all it took to convert my MP3 player into a sophisticated remote control for my digital-music collection. That program, called simply Remote, runs on the iPhone as well as on the iPod touch, a version of the Apple MP3 player that has an iPhone-like touch-sensing screen and Internet-access capabilities using Wi-Fi wireless technology. Remote is available free of charge on the online App Store that Apple has used since July to distribute software for those devices.

In essence, Remote is a remote control for all music stored on a Mac or Windows PC that’s loaded into iTunes, Apple’s music jukebox software. It allows you to jump between playlists, browse artists and pump up the volume. For the program to work, you need to buy into using other Apple entertainment products.

In the simplest setup, Remote lets you control the music from stereo speakers connected directly to a PC. But it’s most useful when you use a PC to deliver audio to additional speakers around a home — say, a pair on the patio and in the living room.

Apple sells a couple of products that receive audio signals from a PC running iTunes. Both work wirelessly over a Wi-Fi home network so you don’t need to put holes into your walls to run computer and speaker wires. I tested Remote using both. One is an Apple TV, a $229 set-top box in my living room that plays digital audio and video through a standard home-theater system. The other is an AirPort Express, a $99 Apple wireless networking device on my patio connected to a pair of powered A5 speakers made by Audioengine, of San Jose, Calif. A third set of speakers was connected to an iMac in the kitchen, where I store all of my digital music. (The least expensive iPod touch costs $299.)

It was a breeze to configure the Apple TV and AirPort Express to show up as remote speakers in iTunes on my computer. Setting up Remote to give me mobile control over this array of speakers was trickier. After installing the program on my iPod touch, I couldn’t get it to work with iTunes on my PC. After 20 minutes of fiddling with the security settings for my Wi-Fi base station, iTunes finally recognized Remote. I was in business.

We all know how confusing the remote controls for TV sets and stereo systems can be. Remote, by contrast, cleanly displays all the music on my PC on the color screen of my iPod touch.

The program let me flip through artists, albums and playlists with simple finger swipes. But I was sorry that Remote doesn’t have a feature in the iPod touch called cover flow that lets users browse their music libraries by flipping through album-cover art. Apple says it may offer the feature in the future.

The software also let me easily turn on and off the music from my speakers in my kitchen, living room and patio. I could have all the speakers on at once — good for a party. The sound was terrific. The crisp-sounding $349 Audioengine speakers don’t require a stereo receiver.

Because Remote uses Wi-Fi to communicate with iTunes, I could control music anywhere around my house and backyard, which are small enough to be fully covered with a signal from my Wi-Fi base station. That’s a big plus over conventional remote controls that use infrared, a technology that doesn’t work through walls.

One drawback: The battery in my iPod touch drained overnight when I configured the device to stay connected to iTunes, a feature that increases software responsiveness. Changing the setting let me go days without recharging my iPod touch, but it meant I had to wait a couple of seconds for Remote to connect to iTunes when I started up the software — an acceptable trade-off.

Another multiroom audio product with a good remote control is the ZonePlayer from Sonos, an equipment maker based in Santa Barbara, Calif. That system has some advantages over Apple’s offerings, including the ability to access tunes from online music services, such as Pandora and Rhapsody, and separate volume controls for each set of speakers.

The Sonos system starts at $999 for a remote control and wireless receivers, without speakers, that can deliver music to two rooms.

For people who already own an iPod touch or iPhone, Remote is a good reason to buy an AirPort Express, and fill your home with music.

Walter S. Mossberg is on vacation.

• Email Nick.Wingfield@wsj.com.

So it was a big deal when Apple (AAPL) announced a new service that, for $100 a year, would bring corporate-type synchronization of email, calendars and contacts to anyone. It was even better that Apple promised that the service, called MobileMe, would work on Windows computers as well as on the company’s own Macintosh computers, iPhones and iPod Touch hand-helds. To top it off, Apple threw in 20 gigabytes of online storage, a suite of Web-based applications, the ability to synchronize browser bookmarks and an online photo gallery.

Unfortunately, after a week of intense testing of the service, I can’t recommend it, at least not in its current state. It’s a great idea, but, as of now, MobileMe has too many flaws to keep its promises.

I am not referring to the launch glitches that plagued MobileMe earlier this month, such as servers that couldn’t keep up with the traffic and email outages that, for some users, persist as I write this. Those were bad, but they have eased considerably. Apple already has apologized for them and is giving customers an extra 30 days on their subscriptions to make up for the poor start. The problems I am citing are systemic.

Here’s how it’s supposed to work. You subscribe to MobileMe and set up a new MobileMe email account, which can also suck in email from your current address. Your MobileMe email is pushed to your Windows computer using your choice of Microsoft (MSFT) Outlook, Outlook Express or the new Windows Mail program. It’s also pushed to your Mac using the built-in Apple Mail program. And it shows up instantly on your iPhone in the phone’s built-in email program.

Similarly, if you add, delete or change a calendar entry or a contact on any of the devices, the change automatically is reflected on all the others. In Windows, the MobileMe calendar shows up in Outlook, and the contacts can be viewed in Outlook, the Windows Address Book or Windows Contacts. On the Mac, the calendar and contacts appear in the built-in iCal and Address Book programs. On the iPhone, MobileMe uses the built-in Contacts and Calendar programs.

Bookmarks can be synchronized using either the Mac or Windows versions of Apple’s Safari Web browser, or Internet Explorer 7 on Windows.

At the MobileMe Web site, using any computer, you can send and receive email via a Web-mail program, and view and edit your calendar and contacts. Changes made on the Web site instantly show up on your computers and your iPhone, and vice versa. Also at the MobileMe Web site, you can maintain a photo gallery and view your online file storage.

But in my tests, using two Macs, two Dell (DELL) computers and two iPhones, I ran into problem after problem. One big issue is that while changes made on the Web site or the iPhone are instantly pushed to the computers, changes made on computers are only synced every 15 minutes, at best. Apple has admitted that this is a problem, and says it is working on it.

But there’s more. The Web site was sluggish, and occasionally calendar entries wouldn’t load at all. Sometimes, you have to manually refresh the Web pages to see changes made on your devices. And when I tried to open my Web-based file-storage page directly from the MobileMe control panel on Windows, I got an error message on both Dells.

My MobileMe calendar, which originated on a Mac, didn’t flow into the main Outlook calendar, but appeared as a separate calendar in Outlook, which was visible only by changing settings. My address-book groups on the Mac, which are simply distribution lists, didn’t show up as distribution lists in Outlook, but as separate address books, and they also weren’t immediately visible. Apple blames Outlook quirks for these issues, but in my view, it should have overcome them.

Other problems abounded. On one occasion, my synced contacts on the iPhone appeared as names only, without any information. In general, synced contacts on the iPhone loaded slowly.

When my Apple Mail program used rules I had set up to automatically file certain emails into local folders instead of leaving them in the inbox, they simply disappeared from my MobileMe account on the iPhone and the Web site. Avoiding this requires a tedious editing of all your rules.

Twice, MobileMe was unable to sync my bookmarks at all, and when it did, their order was scrambled. When I synced contacts to my iPhone, my custom ringtones for particular contacts were lost and had to be reselected.

Apple patiently explained each of my problems, sometimes helping me with workarounds, sometimes claiming they were rare, other times saying that it was working on fixes.

If Apple does get MobileMe working smoothly, it could be a terrific service. But it’s way too ragged now.

• Find all of Walt Mossberg’s columns and videos online, free, at the new All Things Digital Web site, http://walt.allthingsd.com. Email him at mossberg@wsj.com.

This interface is generally called “multitouch,” and it involves using one or more fingers on a screen or touchpad to perform special gestures that manipulate lists or objects on a screen — without moving a mouse, pressing buttons, turning scroll wheels or striking keys.

The best-known example of the interface is on Apple’s iPhone and iPod Touch devices. It allows you, for example, to rapidly flip through photos, lists of emails or song titles by merely “flicking” a fingertip on its screen, or to resize a photo by “pinching” the image with two fingers. And, this month, Apple moved some of these multitouch features onto a laptop, its new MacBook Air, where fingertip actions are performed on an oversized touchpad rather than on a screen.

Apple didn’t invent the multitouch concept. Academic and commercial researchers, and small, obscure companies, have been working on it for years. Apple is adapting the concept, adding its own ideas and popularizing it — just as it did in the 1980s with the mouse and the graphical user interface, which had also been invented elsewhere.

Rival companies are scrambling to add multitouch features to laptops and other digital gadgets. Synaptics, a leading supplier of touchpads for laptop makers who compete with Apple, has announced that shortly it will incorporate several multitouch features into its touchpads. Microsoft is producing a coffee-table-size computer called the Surface, meant for hotels, casinos and retail stores, that uses multitouch finger gestures to move around digital objects such as photos, play games and browse through product options. Hewlett-Packard developed a prototype of a similar multitouch coffee-table computer for home use.

Rotating a photo on Apple’s MacBook Air

And, in the back rooms of this month’s Consumer Electronics Show in Las Vegas, various cellphone makers, seeking to emulate the iPhone, were showing off their own unannounced efforts at multitouch. One prominent cellphone maker, Taiwan-based HTC, has already built a phone, called the Touch, which slaps a rudimentary multitouch interface on Microsoft’s Windows Mobile operating system.

The basic touch screen, of course, is an old and familiar thing. People use them every day to get money from ATMs or to check into flights at airport kiosks. Microsoft’s Tablet computers and Palm’s Treo cellphones, among others, use touch screens that employ styluses or fingers to move cursors, select icons and other items, and even to write on the screen.

But multitouch interfaces are potentially much more versatile. They allow you to use your fingers to manipulate virtual objects on a screen as if they were real, sort of the way Tom Cruise’s character did in the 2002 Steven Spielberg science-fiction film, “Minority Report.” For example, Microsoft’s Surface allows users to rearrange groups of digital photos by just dragging them around on the table top as if they were actual paper prints.

Unlike the touch screens on, say, ATMs, multitouch devices are able to distinguish between the press of a single finger and the press of multiple fingers, and to interpret the motions or gestures you make. They take different actions depending on how many fingers they detect and which gestures a user performs.

On Apple’s MacBook Air, the touchpad still allows you to use one finger to move the cursor and click like a mouse can. But, optionally, it can do much more using multitouch gestures.

You can rotate photos by just touching two fingers to the touchpad and moving the images on the screen as you wish. You can quickly move back and forth through a series of Web pages or photos by “swiping,” or placing three fingers on the touchpad and moving them rapidly sideways. And you can shrink or expand a photo, or zoom in and out on a Web page, by pinching the image.

All recent Mac laptops, not just the new Air, have the optional ability to scroll through a screen without using any button or special zone on the touchpad. You just place two fingers, instead of one, anywhere on the touchpad and drag them across its surface.

In addition to pinching, the new Synaptics touchpads have a feature called “ChiralMotion,” which achieves rapid scrolling by moving two fingers in a circle anywhere on the touchpad. Another Synaptics feature, called Momentum, lets you emulate a trackball by flicking a single finger across the touchpad. This gesture can move an object on screen, like a virtual bowling ball in a game, with the illusion of inertia.

It’s too early to know if the new multitouch approach will ever be as big as the mouse-driven graphical user interface. But it’s already evident that it offers real advantages on devices where a mouse isn’t possible or convenient to use, or the decades-old interface of menus and folders is too cumbersome.

Email me at mossberg@wsj.com. Find all my columns and videos online, free, at the new All Things Digital Web site, http://walt.allthingsd.com.

The latest iPod reinvention expands the line from three models to four, priced from $79 to $399, with capacities ranging from one gigabyte (roughly 240 songs) to 160 gigabytes (up to 40,000 songs.) And that doesn’t count the iPhone, Apple’s much-hyped cellphone, which also includes a full-blown iPod.

I’ve been testing the newest member of the iPod family, the big-screen iPod Touch. It’s a close cousin to the iPhone that connects to the Internet via Wi-Fi wireless networking and replaces the famous iPod click wheel with a touch screen. It starts at $299, $100 less than the iPhone but with the same eight-gigabyte capacity. There’s also a 16-gigabyte iPod Touch for $399.

Like earlier iPods, the Touch is elegant and capable, and works smoothly with Apple’s free iTunes software for Windows and Macintosh PCs, as well as with its computer-based online iTunes Store, which sells far more downloaded songs and TV shows than any other legal outlet.

Not only that, but the Touch introduces a mobile version of the iTunes store. It’s called the iTunes Wi-Fi Music Store, and it allows you to buy, right on the iPod, any of six million songs for the same price you’d pay on a computer. This portable store will soon be made available on the iPhone as well.

For all its beauty and functionality, the Touch has some quirks and downsides. It’s the first iPod model I’ve ever tested that fell significantly short, in my tests, of Apple’s battery-life claims. It’s also the first iPod that lacks any physical buttons for controlling music playback.

The Touch looks, at first glance, like an iPhone that can’t make phone calls. It’s a handsome, thin, black rectangle with a huge 3.5-inch screen — the same size and resolution as the iPhone’s gorgeous screen. But the Touch is even thinner, and a bit shorter.

Like the iPhone, the Touch has just one button on its face, a Home button, which takes you to the main menu, a series of beautiful square icons. And, like the iPhone, the Touch has an on/off button along the top edge. Most everything else is controlled by Apple’s new “multitouch” touch screen interface, which includes a virtual keyboard for text entry.

But unlike the iPhone, the Touch lacks volume-control buttons and a button on its earbuds for pausing or skipping songs. So you have to play, pause and skip songs by touching the screen. This is made easier by a feature the iPhone lacks (so far): If you double-click the home button, music controls appear on the screen, even if the screen is turned off. Still, you can’t control your Touch by touch when you’re listening to music with the device in your pocket or purse.

In my tests, music and video playback went perfectly, and so did viewing photos. The Wi-Fi functions, including the Web browser, a YouTube video viewer and the new mobile store, also worked perfectly.

The Touch is missing some Internet-oriented features from the iPhone that would work well over Wi-Fi. It lacks the iPhone’s email, mapping, stock tracking and weather programs. But its keyboard has a feature the iPhone lacks: As on a BlackBerry, you can insert a period by double-clicking the space bar.

Apple says the Touch was meant mainly to present typical iPod features, not to replicate the iPhone, and it included the Web browser only so users could get onto Wi-Fi to use the mobile music store in certain places that required a log-in screen.

But it seems ridiculous to me to sell a powerful device with Wi-Fi and a huge screen, and to leave out things like an email program, even though you can use Web-based email programs. I assume Apple was concerned that the less costly Touch might compete too much with the iPhone if it had these features. In fact, if somebody can jam a voice-over-Internet capability into the iPod Touch, it might be more of a threat to the iPhone, which is tethered to a single cellphone carrier, AT&T.

The company claims that the Touch can play music for up to 22 hours and video for up to five hours on a single battery charge, even with Wi-Fi turned on. But in my tests, using factory settings, music playback lasted just under 17 hours and video playback lasted just over four hours. Nearly every other iPod I’ve tested, including the new Nano, handily beat Apple’s battery claims.

Also, some early iPod Touch units have had defective screens, where images appeared too dark. Apple says this problem affected a small number of units and is being remedied. My two test units displayed beautiful images.

Despite these downsides, the Touch is a great media player, and the iPod remains the best end-to-end portable solution for playing and purchasing music and video.

Email me at mossberg@wsj.com. Find all my columns and videos online free at the new All Things Digital Web site, http://walt.allthingsd.com.